Possible lifter/rocker/oiling issue with video
And when you installed your friend's 7.400" pushrods you put 7.400 - 7.250 = 0.150" of preload on your lifters. How much internal piston travel do LS7 lifters have available to them?
All of this may account for your noise as well as the gunky chambers after such short run time...valve(s) hung open. Time to check for a bent valve or two.
While you have the head(s) off, place it/them upside down on your workbench and fill the combustion chamber with fluid. A pair of hammer handles usually makes a good spacer to allow the valve tips to clear the bench surface. I use isopropyl alcohol, some use coolant or water. If the valves are sealing properly the chamber will hold the fluid, if not then you'll know immediately.
I used the correct procedure for torquing the rockers when I initially put it together, but the last couple of times I've only just tq'ed them down.
The measurement I got was 7.25 on the adjustable pushrod. From what I've read LS7's should be between .08-.100 preload. 7.25 + .08 = 7.33 which rounds up to the 7.35, or the same as adding .100. If I went with 7.325 then I'd be short of the recommended preload, which I understand causes more noise. Is .08-.100 preload not correct?
The measurement I got was 7.25 on the adjustable pushrod. From what I've read LS7's should be between .08-.100 preload. 7.25 + .08 = 7.33 which rounds up to the 7.35, or the same as adding .100. If I went with 7.325 then I'd be short of the recommended preload, which I understand causes more noise. Is .08-.100 preload not correct?
Time to be "that guy" and give an opinion you probably don't want to hear. I'll be stunned if your problem is a lifter... that noise is REDICULOUSLY LOUD!! My guess, spun rod bearing. Has it always seemed that difficult to turn over and start too? To have two sets of lifters bad, and in the wrong spot both times is very hard to believe. You've swapped rockers, you've swapped lifters, you've swapped pushrods... guess you can try a different set of valve springs, but I'm still saying it's bottom end related. Unfortunately you won't see anything wrong until you get down in there, which means yanking the motor. This sounds a whole lot like my motor when it spun a rod bearing. Hopefully you find out otherwise. Good luck man. Keep us updated.
QUICK EDIT - I just read your first post again. This was a used shortblock??? Did you get to hear the motor run before you put it in? Did you have a machine shop go through it (disassemble, clean, put back together with new bearings, etc.) ? Just struck me as interesting as you say you've had this problem ever since putting in the USED SHORTBLOCK (bottom end).
Another thing you might consider trying (since you're getting good at pulling it apart anyways) is yanking the camshaft back out and seeing if you can see any grooves that a bad lifter might have put in it. Rare, but very possible. Anyways, as I said above, keep us updated.
QUICK EDIT - I just read your first post again. This was a used shortblock??? Did you get to hear the motor run before you put it in? Did you have a machine shop go through it (disassemble, clean, put back together with new bearings, etc.) ? Just struck me as interesting as you say you've had this problem ever since putting in the USED SHORTBLOCK (bottom end).
Another thing you might consider trying (since you're getting good at pulling it apart anyways) is yanking the camshaft back out and seeing if you can see any grooves that a bad lifter might have put in it. Rare, but very possible. Anyways, as I said above, keep us updated.
Last edited by edwardzracing; May 20, 2011 at 01:15 PM.
I initially thought the same thing, but how does a spun rod bearing noise move from the back of the engine to the front? Plus the sound is totally different in person than on the video. It is a distinct tapping noise. Not the usual thud type of noise a spun rod bearing makes. I've heard a few engines with spun bearings and this is not the same noise and is too high up in the engine to be that noise.
I hope you are right, but what else is there left to change in the valvetrain? Did you save your stock stuff (stock pushrods, stock cam, stock lifters, stock oil pump that you know was working prior to the shortblock swap) ? Throw that stuff back in and see what happens. Preload being off by a little bit isn't going to make a noise like that. It would have to be way way off to make a noise like that. Just seems a little scary knowing you purchased a used shortblock without really knowing if there was anything wrong with it. I know people say the things they sell are good, but you never know until you find out the hard way sometimes. I really do hope I'm wrong, because as you already know, pulling the motor SUCKS, but you've done just about everything possible on that top end and the problem still exists and shows no signs of getting better. If you didn't have a machine shop go through it prior to putting it in, then how do you REALLY know that there isn't a problem with it? You've put two different sets of lifters, pushrods, rockers arms on it... noise didn't change did it? I say get that camshaft out of there and take a good look at it... see if you can see any issues there. Drain the oil just for the hell of it to see if you see anything weird there. PROVE ME WRONG MAN, lol. *hoping for the best* Hate to see an issue like this when I just recently fought the same thing.
Last edited by edwardzracing; May 20, 2011 at 03:54 PM.
...pr's being too long might be a valid reason now. Just tightened down all the rockers. As I was hand tightening the with a 1/4 ratchet, EVERY valve springcompressed at least a little before it got tight and ready for the tq wrench. Sure sign that the PR's are too long? Never really paid attention to it before now since Crainholio said something.
And no, I didn't get to hear it run. Came out of another '98 Camaro that was getting a 6.0l swap. Turned over fine by hand, but did not have a machine shop go through it. Bought it for $650 since it was a bare longblock. Chance I knew I was taking but I'm not too much into this build besides time. I'm hoping forthe best too but we will see soon
And no, I didn't get to hear it run. Came out of another '98 Camaro that was getting a 6.0l swap. Turned over fine by hand, but did not have a machine shop go through it. Bought it for $650 since it was a bare longblock. Chance I knew I was taking but I'm not too much into this build besides time. I'm hoping forthe best too but we will see soon
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo I'm not ruling out rod knock, but it's weird the noise move from back to front and it's such a loud tap and not thud.
That sound is not a rod knock. A wrist pin can make a tapping noise, but it will typically get louder under a load such as holding the engine against the brakes. If your sound does not get louder under a load, then it is probably valve train just as you suspect. While it is hard to tell from a video, it sounds like a valve train noise to me.
Working the next couple of days, but I'm going to go ahead and install the stock cam and pushrods in next week to see if that makes a difference. If the noise is still there I guess the engine comes out.
Good call. Let us know what you find out. Good luck man! Another question. Would a bad lifter tray make this noise? There are no visible cracks or warpage on it. And they came with my first set of lifters, only 5,000 miles.
I'm still scratching my head as to my prior valvetrain noise, other than minor grooves on several lobes and lifter rollers (abraded valve tip material washed onto them) I haven't found anything wrong.
My only clue was the noise getting worse when I replaced the valve springs w/ new and stiffer ones.
Good luck & keep us posted.
Alright. Played with it again today. I rechecked the lifter tray since that was the only thing that possibly hasn't been changed that was moved with the first lifter swap. Well I did find a small crack, so I swapped it with another one I had, and still had the same noise. But, I let it run for about a minute and a half or so and the tapping started to become intermediate. But, as it did, that slight squeaking noise started to resurface again. And, there was some other noise I could hear coming from the bottom end that didn't sound good. Sounded like a very very faint knock. Weird that as the car warmed up that the tapping would be intermediate and sometimes disappear for a second or two. But I think I'm gonna go ahead and take this engine out and tear it down. I'm only $650 into the shortblock, so it's not too bad of a loss. At least I have a block now that I can work with, compared to a block with two holes in it, lol.
I will give the stock cam and pushrods a shot first though.
I will give the stock cam and pushrods a shot first though.
At least it sounds like you're making a little bit of progress and hearing a few different things. Keep us posted on what you find. I admire your ability to be positive about it and look forward to the things to come. I'd be livid, lol. Good luck, man!
Brad
Brad
TECH Addict
Joined: Sep 2009
Posts: 2,481
Likes: 5
From: PA/MD
I had to do the same thing, put mine back together, got it in and running, even tuned it....with about 50 miles on it, I lost oil pressure. Pulled the motor out and this time I found the problem. So I went ahead and dropped it off at the machine shop a month ago, and should be getting it back tomorrow.....it will all be worth it when we are done...I hope lol
I'm only positive cause that's the only thing left to be, lol. I was livid about it two weeks ago after the first lifter swap, now I just wanna know what's going on. I think I'm going to skip the stock cam install. I was hearing things I didn't like, and had a guy come by the other day to hear it and he says his made the same kinda sound when he needed a rebuild. The machine shop he took it to said it was a stretched rod end, don't know if that's common or not. But I'm gonna take it out and apart and have a machine shop look it over. Then I'll just do a freshen up with new bearings, rings, and have the rods resized for the arp bolts if everything turns out ok. If not, I might sell the block and put it towards a 6.0L...as I'm not wasting money on new internals for a 5.7 when I can get a running lq4 shortblock for 600-800 and just buy new internals for that.
TECH Addict
Joined: Sep 2009
Posts: 2,481
Likes: 5
From: PA/MD
I'm only positive cause that's the only thing left to be, lol. I was livid about it two weeks ago after the first lifter swap, now I just wanna know what's going on. I think I'm going to skip the stock cam install. I was hearing things I didn't like, and had a guy come by the other day to hear it and he says his made the same kinda sound when he needed a rebuild. The machine shop he took it to said it was a stretched rod end, don't know if that's common or not. But I'm gonna take it out and apart and have a machine shop look it over. Then I'll just do a freshen up with new bearings, rings, and have the rods resized for the arp bolts if everything turns out ok. If not, I might sell the block and put it towards a 6.0L...as I'm not wasting money on new internals for a 5.7 when I can get a running lq4 shortblock for 600-800 and just buy new internals for that.
I think that's a pretty good price for everything